Frey’s
syndrome consists of gustatory discomfort, sweating and flushing of the skin
overlying the parotid area which may be associated with pain in the
auriculotemporal nerve distribution. It is caused by the severed ends of
parasympathetic secretomotor fibres which innervated the salivary gland growing
into the sweat glands of the skin.

Frey’s
syndrome can be socially debilitating and because of the difficulty in its
management, preventive measures should be instituted during the initial
surgery. To our knowledge, the longest latency of Frey’s syndrome after
parotidectomy recorded in the literature is 50 years [1].
Our patient had parotidectomy at the age of 7 years and presented 40 years
later with Frey’s syndrome.

Patient
and case report

A
previously well 47 year old housewife presented to the surgical clinic with a 1
year history of worsening right-sided facial gustatory sweating and flushing
associated with headaches and dizziness. She explained that the gustatory
sweating was now socially embarrassing and she was desperate for a solution. At
the age of 7 years she had undergone a parotidectomy for a parotid mass. There
was nothing in the history to suggest why she had presented now rather than
earlier. Physical examination confirmed a right cervico-mastoid-facial incision
from the previous parotidectomy (Figure
1). She helpfully offered to show the signs as she munched on an apple and
the gustatory sweating and flushing where immediately apparent as shown in figure 2. She was subsequently
referred to the ear nose and throat (ENT) clinic for definitive management.

Discussion

Frey’s
syndrome is a disorder characterised by unilateral sweating and flushing of the
facial skin in the area of the parotid gland occurring during meals. This
syndrome was first described by Lucia Frey, a French neurologist in 1923. This
condition is a sequela of parotidectomy and may follow other surgical, traumatic
and inflammatory conditions of the parotid and submandibular glands. The
presumed pathophysiology process is the aberrant regeneration of cut
parasympathetic fibres between the otic ganglion and the salivary gland tissue
leading to innervation of sweat glands and subcutaneous vessels. Gustatory
stimulation then results in sweating and redness of the skin of the involved
area [2].

The reported incidence of Frey’s syndrome after parotidectomy varies
considerably depending on the method of assessment. Gustatory sweating is
detected in almost 100% of cases, evaluated by means of a post-operative
iodine-starch test (Minor test), but only 10-15% have serious complications [3]. The debilitating symptoms in Frey’s syndrome can be
avoided with good preoperative planning and assessment. Thick skin flap and
partial superficial parotidectomy are the most important techniques to minimize
the risk of developing symptomatic Frey syndrome. An alternative is use of the
superficial musculoaponeurotic system (SMAS) flap which is placed in the bed of
the resected parotid gland. This serves as a protective barrier guarding
against the aberrant anastomotic communications between the postganglionic
secretomotor fibres and the adjacent sweat glands [4]. The
ideal Frey’s syndrome barrier has to either remain in place permanently or be
replaced by dense body fibrosis which prevents the growth of parasympathetic
parotid fibres toward the facial skin sweat glands. In this regard,
e-polytetraflouroethylene (PTFE) implants represent the ideal solution because
of their good biocompatibility, low tissue reactivity and their lack of
resorption. The incidence of Frey’s syndrome is also related to skin flap
thickness in parotidectomy, with thin flaps developing significant symptoms.
Thus Frey’s syndrome is a preventable phenomenon and the potential for its
appearance should be discussed with the patient before surgery in the parotid
gland.

Various methods have been developed to diagnose Frey’s syndrome, including the
Minor’s starch-iodine test, thermography and use of questionnaires for the
subjective assessment of symptoms. The Minor’s starch-iodine test is highly
accurate and will identify asymptomatic patients with Frey’s syndrome.
Thermography is a non-invasive test that provides a qualitative visual analysis
of the cutaneous capillary response in Frey’s syndrome following parotid
surgery.

Various forms of treatment of Frey syndrome, both medical and surgical, have
been tried with varying degrees of success. However, the majority of patients
are satisfied by an explanation of the condition and reassurance [5]. Intracutaneous injection of botulinum toxin is a safe and
effective treatment with long-lasting effects for patients with extensive
gustatory sweating [5]. Its use in Frey’s syndrome was
initiated by Drobik and Laskawi in 1995. The neurotoxin enters the cytoplasm of
nerve cells by endocytosis and neurotransmission is blocked until
re-innervation occurs by collateral growth of fibres. Severe symptoms may
justify tympanotomy and division of Jacobson’s nerve on the promontory of the
medial wall of the middle ear.

Conclusion

This
case report serves to provide additional evidence of the possibility of a
long-delayed clinical presentation of Frey’s syndrome post-parotidectomy.
Frey’s syndrome can be socially debilitating and because of the difficulty in
its management, preventive measures should be instituted during the initial
surgery. Furthermore, patients should be warned of the possibility of this
long-delayed clinical presentation.

Figures

Figure 1: Shows a
right cervico-mastoid-facial incision from a previous parotidectomy at the age
of 7 years